The aim of this study is to investigate the role of circulating tri-glyceride-fatty acids in lung metabolism and surfactant synthesis. Tri-glycerides do not penetrate the endothelial barrier. Chylomicron and very low density lipoprotein bound triglycerides are first hydrolyzed by lipoprotein lipase on the endothelial surface. The factors affecting triglyceride-fatty acid uptake by the lung will be investigated in an isolated, ventilated and perfused preparation. The following hypothesis will be tested: 1. triglyceride-fatty acid is essential in lung energy and/or surfactant metabolism; 2. lipoprotein lipase activity is an indicator of endothelial function and 3. lung endothelium might selectively remove or modify chylomicron remnants and very low density lipoproteins and by this action protect the systemic circulation from atherogenic substances.